In an interview with CNN's Wolf Blitzer on Monday, Paul said he would boycott the Fox Business debate and called the network's decision a "mistake."

"It's a mistake because the thing is we actually have been in the top five or six in most of the recent polls. In fact, last week in a national poll we were just one point out of fourth place. So I think it's a mistake to try to exclude me from the national debate," he said.

"I won't participate in anything that's not first tier because we have a first tier campaign," the Kentucky senator told Blitzer.